Table 1 Differential diagnosis of ITP and suggested tests to exclude the alternative causes of thrombocytopenia
From: How we treat primary immune thrombocytopenia in adults
Alternative diagnosis | Clinical characteristics | Laboratory tests |
|---|---|---|
Pseudothrombocytopenia | No thrombocytopenia-related symptoms (in vitro phenomena) | Platelet clumping on blood smear due to EDTA-dependent agglutinins |
Acute or chronic Infections (HBV/HCV/HIV/EBV/CMV/B19/Zika/H. pylori) | High-risk populations History, suggestive symptoms or signs | Serologic and PCR tests for viral infection Urea breath test for H. pylori |
Drug-induced (heparin, quinine, antibiotic, NSAIDs, etc.) | History of drug exposure | Drug-dependent antibody tests |
Vaccine-associated | Recent history of vaccination (< 6 weeks) | – |
Connective tissue diseases (SLE, rheumatoid arthritis, anti-phospholipid syndrome, etc.) | Fever, rash, arthralgias, mouth ulcers, hair loss, abortions, and thromboembolism | Targeted serologic tests (ANAs, anti-dsDNA antibodies, anti-CCP antibodies, APLAs, etc.) |
Lymphoproliferative disorders (CLL, Hodgkin’s lymphoma, etc.) | Fever, weight loss, night sweats, lymphadenopathy, splenomegaly | Lymph node biopsy, bone marrow examination, imaging examination |
Immunodeficiency syndrome (common variable immunodeficiency) | Young age, recurrent infections, colitis, lymphadenopathy | Ig levels, lymphocyte ph, genetic testing |
Evans syndrome | Hemolysis and thrombocytopenia | Coombs test |
Bone marrow malignancy (MDS, leukemia, etc.) | Suggestive symptoms or signs (fever, splenomegaly, bleeding, etc.) | Blood smear, bone marrow examination |
AA | Pancytopenia | Blood smear, bone marrow examination |
Thrombotic microangiopathy (thrombotic thrombocytopenic purpura, hemolytic uremic syndrome) | Hemolysis, neurologic symptom, fever, renal damage | Blood smear (schistocytes), haptoglobin, LDH, ADAMTS13 level |
DIC | Precipitating events, severe patients, multiple organ damages | Coagulation tests, blood smear |
Inherited or congenital diseases (Wiskott–Aldrich syndrome, Bernard–Soulier syndrome, MYH9-related disease, type IIb vWD, etc.) | Young-onset thrombocytopenia, family history, congenital abnormalities (deafness, cataract, development delay) | Blood smear, genetic testing |